//! Domain error types for the IAM (auth) module.
//!
//! Typed error enums replace `anyhow::Result` in domain traits and
//! application services, enabling callers to match on specific error
//! variants (e.g. `NotFound` vs `Conflict`) rather than string-checking.
//!
//! # Components
//!
//! - [`RepositoryError`] — persistence-layer errors (not found, conflict, I/O)
//! - [`ServiceError`] — use-case / orchestration errors (config, state
//!   mismatch, provider failures)

use std::fmt;

use crate::error::DomainError;

/// Shared repository error type for IAM persistence operations.
pub type RepositoryError = DomainError;

/// Errors from service / use-case operations in the IAM domain.
#[derive(Debug)]
pub enum ServiceError {
    /// A repository operation failed.
    Repository(DomainError),
    /// The provided configuration is invalid.
    InvalidConfig(String),
    /// OAuth state mismatch — possible CSRF attack.
    StateMismatch,
    /// The OAuth provider returned an error.
    OAuthProvider(String),
    /// A generic error with a message.
    Other(String),
}

impl From<DomainError> for ServiceError {
    fn from(err: DomainError) -> Self {
        ServiceError::Repository(err)
    }
}

impl fmt::Display for ServiceError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ServiceError::Repository(err) => write!(f, "repository error: {err}"),
            ServiceError::InvalidConfig(msg) => write!(f, "invalid configuration: {msg}"),
            ServiceError::StateMismatch => {
                write!(f, "OAuth state mismatch — possible CSRF attack")
            }
            ServiceError::OAuthProvider(msg) => write!(f, "OAuth provider error: {msg}"),
            ServiceError::Other(msg) => write!(f, "{msg}"),
        }
    }
}

impl std::error::Error for ServiceError {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        match self {
            ServiceError::Repository(err) => Some(err),
            _ => None,
        }
    }
}